why is zero called zero in nightmare before christmas

The character of Zero in "The Nightmare Before Christmas" is a skeletal dog who serves as the companion and assistant to Jack Skellington. Zero is named after the number zero because it is a symbol of emptiness, nothingness, and the absence of life. In the context of the story, Zero's name reflects his role as a creature of the dark and the void, who brings a sense of gloom and despair to the otherwise festive and colorful world of Halloween Town. The name "Zero" is also a reference to the character's lack of a physical body, as he is just a skeleton with no flesh or skin.